Hi All,
A C library I'm using has a number of functions that all require a
struct as an argument. The example module shows how to make a new
Python Object from C code and I've seen other posts that recommend this
way of doing it.
In this case though, it would seem easier if I could create the object
in the Python code. This would require storing a pointer to an
instance of the struct until a certain function is called.
I can get the pointer into the python code, but whenever I try to use
it to call another function, the module segfaults. Can anyone suggest
why this is?
static PyObject *
libpyq_PQconnectdb(PyObject *self, PyObject *args)
{
PGconn *conn = PyMem_New(PGconn, sizeof(PGconn *));
conn = (PGconn *)PQconnectdb((const char*)
PyString_AS_STRING(args));
printf("%p", conn);
return PyLong_FromVoidPtr(conn) ;
}
static PyObject *
libpyq_PQfinish(PyObject *self, PyObject *args)
{
printf("%p", args);
return 1;
}
>>> import libpyq #works fine
>>> conn = libpyq.PQconnectdb #conn now a pointer
>>> libpyq.PQfinish(conn) #segfaults
I'm new to C but relatively experienced with Python. I have a sneaky
suspiscion there's a good reason for not doing it this way but I
haven't seen a good explanation of why not yet. If you know one,
please tell me.
Thanks,
Andy
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